Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
NMR Biomed. 2023 Aug;36(8):e4924. doi: 10.1002/nbm.4924. Epub 2023 Mar 27.
The purpose of the current study was to develop and evaluate a three-dimensional single Breath-hOLd cardiac T mapping sequence (3D BOLT) with low-rank plus sparse (L + S) reconstruction for rapid whole-heart T measurement. 3D BOLT collects three highly accelerated electrocardiogram-triggered volumes with whole-heart coverage, all within a single 12-heartbeat breath-hold. Saturation pulses are performed every heartbeat to prepare longitudinal magnetization before T preparation (T -prep) or readout, and the echo time of T -prep is varied per volume for variable T weighting. Accelerated volumes are reconstructed jointly by an L + S algorithm. 3D BOLT was optimized and validated against gradient spin echo (GraSE) and a previously published approach (three-dimensional free-breathing cardiac T mapping [3DFBT2]) in both phantoms and human subjects (11 healthy subjects and 10 patients). The repeatability of 3D BOLT was validated on healthy subjects. Retrospective experiments indicated that 3D BOLT with 4.2-fold acceleration achieved T measurements comparable with those obtained with fully sampled data. T measured in phantoms using 3D BOLT demonstrated good accuracy and precision compared with the reference (R > 0.99). All in vivo imaging was successful and the average left ventricle T s measured by GraSE, 3DFBT2, and 3D BOLT were comparable and consistent for all healthy subjects (47.0 ± 2.3 vs. 47.7 ± 2.7 vs. 48.4 ± 1.8 ms) and patients (50.8 ± 3.0 vs. 48.6 ± 3.9 vs. 49.1 ± 3.7 ms), respectively. Myocardial T measured by 3D BOLT had excellent agreement with 3DFBT2 and there was no significant difference in mean, standard deviation, and coefficient of variation. 3D BOLT showed excellent repeatability (intraclass correlation coefficient: 0.938). The proposed 3D BOLT achieved whole-heart T mapping in a single breath-hold with good accuracy, precision, and repeatability on T measurements.
本研究旨在开发和评估一种基于低秩稀疏（L+S）重建的三维单次屏气心脏 T mapping 序列（3D BOLT），用于快速进行全心 T 测量。3D BOLT 在单次 12 次心跳屏气中采集三个全心脏覆盖的高度加速心电图触发容积，每个容积的 T 准备（T-prep）或读出前，使用饱和脉冲对纵向磁化进行准备，并且 T-prep 的回波时间根据容积进行变化以实现可变 T 加权。加速容积通过 L+S 算法联合重建。在体模和人体（11 名健康受试者和 10 名患者）中，3D BOLT 分别与梯度回波自旋回波（GraSE）和之前发表的方法（三维自由呼吸心脏 T 映射[3DFBT2]）进行了优化和验证。在健康受试者中验证了 3D BOLT 的可重复性。回顾性实验表明，在 4.2 倍加速的情况下，3D BOLT 实现的 T 测量结果与全采样数据相当。在体模中使用 3D BOLT 测量的 T 值与参考值相比具有很好的准确性和精密度（R>0.99）。所有体内成像均成功，使用 GraSE、3DFBT2 和 3D BOLT 测量的健康受试者左心室 T s 平均值相当且一致（分别为 47.0±2.3、47.7±2.7 和 48.4±1.8 ms）和患者（分别为 50.8±3.0、48.6±3.9 和 49.1±3.7 ms）。使用 3D BOLT 测量的心肌 T 值与 3DFBT2 具有很好的一致性，均值、标准差和变异系数均无显著差异。3D BOLT 显示出极好的可重复性（组内相关系数：0.938）。所提出的 3D BOLT 能够在单次屏气中实现全心 T 映射，在 T 值测量方面具有很好的准确性、精度和可重复性。
